Switch for refrigerating apparatus



May 21, 1940. c. D. GRAHAM r 0 swnca FOR REFRIGERATING APPARATUS FiledJuly 51, 1935 2 sheets-sheet 1 BY a 6 AZQRNEYS Why 21, 1940. c. D.GRAHAM 2,201,759

' swn'ca r'on nnmmmzuma APPARATUS Filed Jui 31, 1935 I 2 SheetsSheet 2Patented May 21, 1940 SWITCH FOR REFRIGERATING APPARATUS .Charlcs D.Graham, Dayton, Ohio, assignor to General Motors Corporation, Dayton,Ohio, a corporation oi Delaware Application July 31, 1935, Serial No.34,028

9 Claims. (Cl. ZOO-84) This invention relates to apparatus forconditloning air or other gases.

An object of this invention is to provide an improved control iorapparatus in which air or other 5 gases are conditioned by a medium thespecific gravity of which is to be regulated in order to im part properconditions to the fluid being treated. Further objects and advantages ofthe present invention will be apparent from the following del scription,reference being had to the accompanying drawings, whereina preferredform of the present invention is clearly shown.

In the drawings: Fig. l is a diagrammatic representation of an '5apparatus embodying features of this invention; Fig. 2 is anenlargedvertical cross-sectional view of the switch mechanism;

Fig. 3 is an end view of the mechanism shown in Fig. 2; A Fig. 4 is awiring diagram showing the electrical controls for the system shown inFig. l; and Fig. 5 is a diagram, somewhat similar to that shown in Fig.4, but showing the use of relays.

An apparatus embodying features of this inven- 25 tion includes, ingeneral, an air or gas condltion ing unit i0 which conditions the air orgases for the compartment ii. It also includes a regenerating unit I!which is used to maintain the specific gravity of the body of liquid i3,such as a 30 water solution of a lithium halide salt. within desiredlimits. Air or other gas to be conditioned enters the unit In throughthe inlet conduit i4. This air or gas may come from the compartment llthrough the pipe i5, or from the outside 35 through the pipe 18, orboth. It may pass through a filter ii of any suitable construction.Bailies l I are also provided. The air passes upwardly through a gas andliquid contact tower i8, thence through an eliminating filter 20 and 40is forced by the fan 2|, driven by the motor 22, through the pipe 23 tothe compartment ii, into which it is discharged through the grille 24.Hy-

groscopic liquid, such as lithium chloride water solution, is sprayed onthe contact mass I! by 45 means of a revolving distributor head 25, sothat the liquid trickles over the mass i9 and through the screen 26 andis gathered at the sump 21 from whence it returns through the pipe 28 tothe tank 29 which holds the main body of liquid i3.

50 The distributor head 25 may be a freely rotatably mounted pipe withtangential openings, so that the discharge of liquid rotates the pipe.

Liquid from the main body I 3 is delivered to the conditioner lit bymeans of a. pump 30 driven 55 by a motor 3i The liquid ilows through aninner pipe of the interchanger 32 and is delivered through the pipe 33to the distributor head 25. Cooling liquid, which may be ordinary citywater, or artificially cooled water, enters through the pipe 34 into theouter pipe of the interchanger 32 5 and is discharged at the outlet 35.

A small portion of the liquid discharged by the pump 30 flows throughthe pipe 36 to a box 31 in which the hydrometer element 38 is placed.The liquid in box 31 is therefore representative, as to specificgravity, of the liquid in body i3. A small opening or pipe 39 is placednear the bottom of the box 31. The flow capacity of the opening 38 ismade smaller than that of the pipe 36 so that when the pump 30 operates,the box 31 is filled and overflows at the point 40 as well as throughthe opening 39. When the pump 30 stops the box 31 is emptied down to thelevel of the opening 33. The hydrometer element 38 con trols the switchelement M in response to the specific gravity and the level of theliquid in box 31 in a manner to be more fully described. The liquid inthe main body I 3 is regenerated by pumping a portion thereof by meansof the pump 42 through the heater 4!, from whence the heated liquid isdischarged by the distributor head 44 on the contact mass 45 throughwhich the liquid trickles and drains through the openings 46 back intothe main body 13. Air is caused to flow through the contact mass 45 incontact with the heated liquid and this reconcentrates the liquid. Thisis accomplished by providing a blower 4i, driven by a motor 48, whichblower draws air through the inlet 48 in the tank 29 and causes the airto flow upwardly through the Openings 46 and through the mass 45, and topass through the screen 50 into the inlet of the blower 41. From thencethe moisture laden air is discharged through the pipe 5| to the outsideof the building.

The heater 43 may be of any suitable construction, but preferably is ofthe type in which a sinuous pipe is provided through which the liquidflows. This pipe may be heated by a gas burner 52 provided with a pilotlight and tube 53, The burner 52 is controlled by a solenoid valve 54and by a thermostatic valve 55. The valve 55 is controlled by athermostat 56 placed at the outlet end of the heater 43 in such a mannerthat the flow of gas to the burner 52 is throttled when the liquiddischarged from the heater 43 reaches a 50 predetermined temperature,and thus maintains the discharge temperature of the liquid substantiallyconstant.

The switch element 4| preferably comprises two switches 60 and 61 or themercury tube type. The 5 shown in Figs. 4 and 5. The motor switch 68 ismounted on a rocker arm 62 pivoted on the fulcrum. bar 63. The mormt 68aof the switch 69 is secured to the arm 62 by screws Sill). The switch 6!is suspended from the rocker arm 60 which is mounted on the fulcrum bar85. The mount 61a is secured to the arm El i by screws Gib. The bars 63and 65 'may be provided with triangular fulcrum surfaces 63a and 65.1respectively, at both of their ends and may fit in openings 65 and G7 inthe U-shaped base member 68. The rocker arm G2 is provided with a pin 69to which the connecting rod '59 is secured, the rod being also connectedto the hydrometer element As the hydrometer element 38 rises and fallsin the liquid, when the box 3'! is full, in response to changes inspecific gravity of the liquid, it causes a slight rocking movement ofthe arm 52 which in turn causes the mercury drop H to open and close thecontacts Z2.

A lost motion connection is provided between the switch 5! and theswitch (it or the hydrorneter element 38. This may be accomplished byproviding a screw T3, which may be adjusted into and out of the arm 62.The head i l of this screw is adapted to hit on the end of the screw '15which is adjustably placed in the arm Another screw '16 is positioned sothat its head ll contacts with a pin '28 secured in the arm 62. Theamount of lost motion between the switches (59 and Bi can thus beadjusted toany dwired extent.

The fulcrum bar '53 is kept in place by cars 'iil secured to the upperends of the base 63 by means of screws '39s. The fulcrum bar'65 is keptin place by ears 191) secured to the base member Ed by 35 means ofscrews 150.

The setting to which the switch E9 is responsive with respect to thespecific gravity of liquid in the box 3'? may be adjusted by means ofweights 8B, which may. be moved along the length of the arm 62 by aturning movement on the threads 8 i. This alters the upward pull uponthe float rod '50 thus altering the eiiective weight ofthc float 38 andthereby determining the specific gravity of the liquid at which thecontacts 78 are closed. Likewise adjustable weights 82 are provided atthe end of the arm 64. These weights are so adjusted that when the box37 empties, then the weight of the hydromcter clement 38, no longerfreely floating in liquid, is sufiicient to rock both arms 52 and ildownwardly so that the mercuri drop 83 opens the contacts 84. A stopmember 85, in the shape of a U bar is secured to the brass member 58 bymeans of bolts 85a and prevents the right end of the rocker arm 82 fromrising beyond a predetermined limit, this limit being such that the arm82 is left free to rock in response to specific gravity changes of theliquid in the full box 3'1 and to open and close the contacts '12 aslong as the box 31 remains full. However, when the box 3'! empties, andthe hydrometer element 38 no longer can float in liquid, then the arm 62swings downwardly and causes the head 76 to impinge against the screw 75which in turn rocks the arm 66 and opens the contacts 86. The switch 6!is therefore responsive to the level of the liquid in box 3?.

The switch structure M is used to control the various electricalelements shown in Fig. 1. The method of control is indicated in thediagrams 22 which drives the blower 2|, is placed across the power linesSill, ill under the control of the manual switch 92. When the switch 92is closed, air cir-- culation is insured for the compartment i i. If itis desired to condition this air, then the manual switch 93 is alsoclosed. A condition responsive element 8 3 is provided in thecompartment ii. This may be responsive to relative humidity, or to wetbull: temperature or both, or it may be made responsive to "effectivetemperature, which a temperature in which the dry bulb and relativehumidity are functions. The control element 94 is provided with a switch(not shown), which when closed energizes the solenoid 85 and the motor3i which drives the pump Bil. This causes hygroscopic liquid to bepumped from the main body 13 over the contact mass i9 and condition ordry the air passing through the unit 38. At the same time the solenoid95 opens the valve 96 and causes cooling liquid or water to flow throughthe interchanger and to impart desires temperature to the hygroscopicliquid before it is delivered to the mass 19. Soon after the pump 35 isthus started, the box 3? is filled causing the hydroineter element 321to assume a position which is representative oi the specific gravity ofthe main. body of liquid iJ. If the specific gravity is insuiiicient,the hydrometer element 33 tends to sink within the liquid causing themercury bulb E? to flow to the right and to close the contacts 72. Whenthe box 3? is full, the normal position of the switch 66 is a closedposition, and under such circumstances current can flow through the line9?, through the contacts 8-! and through the contacts ?2 to the motorsill and 02a and to the solenoid gas valve M. This causes the blower 3-?to circulate air through the regenerai-or and causes the pump 2 to pumpliquid through the roseneratorand permits the burner 52 to be suppliedwith gas under the control of thermostatic valve Thus as long as theinstrument requires air conditioning, the pump 36 is caused to operateand to supply liquid to the air conditioner and to the box 3?. When thebox 3'! is maintained full the hydrometer element 38 controls theoperation of the regenerator and iis members causing regeneration totake place, if necessary. However, when the instrument 94 opens thecircuit to the motor 3!, which drives the pump 30, then box 87 is nolonger supplied with liquid from the pipe 36 and becomes empty. Whenthis occurs, the hydrometer element 38 no longer floats freely in liquidand thus moves the arm 6?. downward a sufiicient amount to move also thearm it and to open the contacts 8 This prevents operation of theregenerator elements until such a time as air conditioning is againrequired.

Fig. 5 is substantially the same as Fig. 4 except that a relay I012 isinterposed between the control and the electrical element to becontrolled thereby, and relay i! is interposed between the switchelement it and the elements to be con trolled thereby, thus reducing theamount of current which must flow through the switch elements. Theremainder of the circuit shown in Fig. will be readily understood fromthe de scription given with respect to Fig. 4.

While the form of embodiment oi. the inven tion as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A control for gas conditioning apparatus or the like, comprising abox, flow means for flowing liquid into said box to fill said box to apredetermined level, means for changing the specific gravity of the saidliquid, a drain opening, of less flow capacity than said flow means, ahydromcter element inisaid box adapted to float in liquid in said boxopened an closedby said hydrometer element in response the specificgravity of liquid whe 5 said box filled, and a second switch havincontacts altered by a fall in liquid level in said box one i saidswitches being provided with means to avoiding the operation of thesecond switch w en the first switch is operated by varia- 1o tions in te specific gravity of theliquid.

l6 gravity 1 the said liquid, a drain opening oi less flow ca acity thansaid flow means, a hydrometer eleme t in said box adapted to fioat inliquid in said x when filled, a flrst switch, a first switcharm/connected to said switch andto said hydro eter element, a secondswitch, and a second sw tch arm having a lost motion connection with sid first switch arm whereby said first switch is esponsive to specificgravity conditions of liquid when said box is filled and whereby saidsecond switchv is responsive to the level of liquid in said box.

3. A control for gas conditioning apparatus or the like, comprising abox, flow means for fiowing liquid into said box to fill said box to apre- 80 determined level, means for changing the specific gravity of thesaid liquid, a drain opening of less fiow capacity than said flow means,a hydrometer element in said box adapted to fioat in liquid In said boxwhen filled, a first switch, a first switch 86 arm connected to saidswitch and to said hydrometer element, a second switch, and a secondswitch arm having a lost motion connection with said hydrometer elementwhereby said first switch is responsive to specific gravity conditionsof liquid when said box is filled and whereby said second switch isresponsive to the level of liquid in said box.

4. A control for gas conditioning apparatus or the like, comprising abox, flow means for flowu ing liquid into said box to fill said box to apredetermined level, means for changing the specific gravity of the saidliquid, a. drain opening of less flow capacity than said flow means, ahydrometer element in said box adapted to float in liquid in said boxwhen filled, a first switch, a first switch arm connected to said switchand to said hydrometer element, a second switch, and a second switch armhaving a lost motion connection with said first switch arm, said lostmotion connection 66 being adjustable, whereby said first switch isrehen filled, a switch having contacts the changing of said contacts, asecond switch having contacts and being connected by lost motion to saidhydrometer element whereby said second switch is responsive to changesin level of the liquid with which said hydrometer ele- 6 ment isassociated.

6. A control comprising a hydrometer element, a (n-st switch havingcontacts and being connected to said element to be responsivetc specificgravity of liquid with which said element is asso- 1d elated, a secondswitch having contacts and being connected by lost motion to saidhydrometer element whereby said second switch is responsive to changesin level of said liquid, and means for adjusting said lost motion. 15

7. A control means including a float chamber, means operable to maintaina predetermined level of liquid within said float chamber, means forchanging the level of liquid in said fioat chamber when said first namedmeans is inopera- 20 tive, a float within said float chamber, afirstswitch means connected to said fioat and opened and closed byvariations in the specific gravity of the liquid in the fioat chamberwhen said first named means is operative, and a second switch 26 meansoperated by said float when the level of the liquid in said floatchamber is changed materially from said predetermined level, one oi saidswitch means being provided with means for avoidin operation of thesecond switch means when the 80 first switch means is operated byvariations in the specific gravity of the liquid.

8. A control means including a float chamber, means operable to maintaina predetermined level of liquid within said fioat chamber, means 35 forlowering the level of liquid in said fioat chamber when said first namedmeans is inoperative,

a float within said float chamber, a first switch means connected tosaid fioat opened by a rise in specific gravity and closed by-a fall inspecific 4c gravity when said predetermined level is maintained, and asecond switch means moved to open position by said fioat when the liquidlevel falls materially below said predetermined level, one or saidswitch means being provided with a lost 66 motion connection foravoiding operation of the second switch means when the first switchmeans is operated by variations in the specific gravity.

9. A control means including a float chamber, means operable to maintaina predetermined level of liquid within said fioat chamber, means forchanging the level of liquid in said float chamber when said first namedmeans is inoperative, a float within said fioat chamber, a first switchmeans connected to said float and'opened and closed by variations in thespecific gravity of the liquid in the float chamber when said firstnamed means is operative, and a second switch means operated by saidfloat when the level of m the liquid in said float chamber is changedmaterially from said predetermined level, said second switch meanshaving a lost motion connection to said float.

CHARLES D. GRAHAM. I

